Biology subjects

Cavieres, L. A.

Publications and source records attributed to Cavieres, L. A..

4 recordsLinked to original sources

bioRxiv2025

Growth temperature trigger adjustments in net photosynthesis of high-elevation plants from the Andes of Central Chile

Temperature significantly influences plant morphology and photosynthesis at high altitudes, shaping distinct altitudinal patterns. Lower temperatures at higher elevations typically increase leaf mass per unit area (LMA), potentially reducing mesophyll CO2 diffusion (gm) and chloroplast CO2 availability, which can limit photosynthetic rates (AN). However, most evidence comes from field studies where elevation-related factors, like gas pressure, water, and light, covary. Habitat type further affects plant responses, as wetland (azonal) plants may be more sensitive to thermal changes due to waters buffering effect on temperature fluctuations. To isolate temperature effects, we conducted a controlled experiment with plants from two elevations (2600 and 3550 m a.s.l.), exposing them to two daytime temperatures (15 and 20 {degrees}C). We measured LMA, gm, and AN. Growth temperature significantly influenced photosynthesis and gm but not LMA. Plant origin and habitat type (zonal vs. azonal) also shaped responses. Our findings reveal that temperature impacts photosynthesis by altering mesophyll diffusion independently of LMA. Furthermore, adaptations to specific elevations and environments, such as wetlands, contribute to the variability in responses. This study highlights the nuanced role of temperature in shaping photosynthetic traits in mountain plants. HighlightDifferent growth temperatures affected photosynthesis independently from LMA, the response also varied from wetland species compared to non-wetland species and from plants coming from low or high elevation.

plant biology↗

bioRxiv2024

Darwin's Naturalization Conundrum explained by gradients of environmental stress and disturbance

Darwins Naturalization Conundrum (DNC) states that non-native species closely related to the native community are either more likely to succeed because shared adaptations help them overcome environmental filtering, or less likely to succeed because of strong competition with their native relatives. Despite extensive research, no general patterns have so far emerged. One reason may be that the relative importance of competition and environmental filtering depends on environmental conditions. To test this hypothesis, we conducted a global assessment of DNC examining patterns of phylogenetic relatedness of non-native plant species to the native community along gradients of elevation and anthropogenic disturbance in mountains. Phylogenetic distance of non-native to native species decreased with increasing elevation and in disturbed plant communities. Our results help resolve DNC by showing that the environmental context sets expectations for patterns of relatedness between non-native and native species and helps illuminate the ecological and evolutionary processes generating these patterns.

ecology↗

bioRxiv2024

Environmental versus litter traits as drivers of microbial decomposer functions

Plant litter decomposition is a key ecosystem process with significant implications for global carbon cycling, soil fertility and plant productivity. Given that microbial decomposers are the main players in the decomposition process, it is surprising how little is known about their functional diversity in different habitats or their ability to respond to environmental changes. To fill this knowledge gap, we conducted a litterbag decomposition experiment along a pronounced climate and vegetation gradient in the Chilean Coastal Cordillera (26{degrees}S to 38{degrees}S), ranging from hyper-arid to temperate, using mixtures of four plant species, native to the respective ecosystems. We analyzed potential decomposition functions of bacterial and fungal litter communities along with their biotic (litter traits) and abiotic (meteorological conditions and soil properties) environments, to determine the relative importance of these environmental factors for microbial community functioning. We also tested the impact of the functional diversity of the decomposer communities (i.e., the diversity of decomposition related functions) on litter mass loss. Functional composition was related most strongly to the temporal variation of precipitation and radiation, explaining about 19 % and 6 % of variation in bacteria and fungi, respectively. In contrast, functional diversity was quite strongly related to litter chemical traits (C:N, C:P, tannins, phenols). Litter mass loss after six months of decomposition was not correlated to the functional diversity of decomposer communities but increased with the presence of habitat generalists like Proteobacteria, Actinobacteria, Firmicutes, and Bacteroidetes. Taken together, these results highlight i) the interplay between abiotic factors and chemical litter traits on litter microbial functions and functional diversity and ii) the importance of microbial generalists for litter decomposition across different ecosystems. These results enhance our ability to predict changes in microbial decomposer communities and litter decomposition under future climate-change scenarios.

ecology↗

bioRxiv2022

Assessing the accuracy of paired and random sampling for quantifying plant-plant interactions in natural communities

Interactions among plant species in extreme ecological systems are often inferred from spatial associations and quantified by means of paired sampling. Yet, this method might be confounded by habitat-sharing effects, in particular when microenvironmental heterogeneity and stress are high. Here, we address whether paired and random sampling methods provide similar results at varying levels of environmental heterogeneity. Furthermore, we investigate how the relationship between species preferences and abiotic severity influences the outcome of these two methods. We quantified spatial associations with the two methods at three sites that encompass different micro-environmental heterogeneity and stress levels: semi-arid environments in Canary Islands, Spain and Sardinia, Italy and a cold alpine environment in Hokkaido (Japan). Then, we simulated plant communities with different levels of species micro-habitat preferences, environmental heterogeneity and stress levels. We found that differences in species associations between paired and random sampling were indistinguishable from zero in our model simulations. At each site, there were strong differences between beneficiary species in their spatial association with benefactor species, and associations became more positive with increasing stress in Spain. Most importantly, there were no differences in the results yielded by the two methods at any of the different stress levels at the Spanish and Japanese sites. At the Italian site, although micro-environmental heterogeneity was low, we found weakly significant differences between methods that were unlikely due to habitat-sharing effects. We conclude that the paired sampling method can provide significant insights into net, long-term effects of plant interactions in spatially conspicuous environments.

ecology↗